Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens and the like. Touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch screens can include a touch sensor panel, which can be a clear panel with a touch-sensitive surface, and a display device such as a liquid crystal display (LCD) that can be positioned partially or fully behind the panel so that the touch-sensitive surface can cover at least a portion of the viewable area of the display device.
Touch screens can allow a user to perform various functions by touching the touch sensor panel using a finger, stylus or other object at a location often dictated by a user interface (UI) being displayed by the display device. In general, touch screens can recognize a touch and the position of the touch on the touch sensor panel, and the computing system can then interpret the touch in accordance with the display appearing at the time of the touch, and thereafter can perform one or more actions based on the touch.
On-screen keyboards, such as virtual keyboards on touch screens, are widely used in portable computing devices, but do not offer the same tactile feedback as conventional keyboards. For example, the tactile feel and sound of the depression of mechanical keys, which can be useful in providing feedback to the typist on the accuracy and completion of keystrokes, can be missing from a virtual keyboard. As a result, a typist's fingers can drift with respect to the location of the virtual keys. In addition, when thumb typing is desired or necessitated by the size or location of the virtual keyboard, the typist's thumb or thumbs can also drift or miss the mark with respect to the location of the virtual keys. In particular, when single-thumb typing is necessitated on a larger virtual keyboard, it can be difficult to reach the virtual keys on the inner part of the device that are farthest away from the thumb.